Historically, the conversion of coal and other carbonaceous matter to acetylene by means of electric arc heaters, and in particular other heating devices, are well-known.
Conventionally, carbonaceous matter, together with hydrogen, are heated by an electric arc device or other suitable source of heat. The mixture is heated so that the carbonaceous matter decomposes. The composition that is produced as a result of the decomposition of the carbonaceous matter will depend on the reaction conditions existing in the decomposition or reaction zone. It is well-known that the formation of certain compositions are favored under specified reaction conditions. For example, the formation of acetylene as an intermediate product is favored where the temperature of the reaction zone is above 1300 K. The formation of acetylene relative to the simultaneous decomposition of acetylene is also favored at or near 1300 K.
In U.S. Pat. No. 1,757,454, there is a process whereby water vapor is employed as the suspension agent for coal dust. The combination is fed to an electric arc where a chemical reaction produces acetylene.
Another arc coal/acetylene conversion process is described in U.S. Pat. No. 2,916,534, which was reissued as RE 25,218. The process described in this patent makes use of hot hydrogen molecules which are partly or totally dissociated into atoms to decompose hydrocarbons. This patent also specifies a specific flow rate of hydrogen gas through the reaction zone and also the mole ratio of gas to carbon in the hydrocarbons.
U.S. Pat. No. 3,217,056 is another patent which utilizes the heat available in atomic hydrogen to decompose carbonaceous matter. The heat content of the hydrogen gas and also reaction times are specified.
U.S. Pat. No. 4,010,090 makes use of a hydrocarbon gas stream to increase the length of an arc before coal or other carbonaceous matter is provided to the arc. The principal virtue of this patent relative to the invention is the large number of other patents relative to arc reactors disclosed in column 2, lines 11-17.
U.S. Pat. No. 3,395,194 describes a partial oxidation process using an electric arc device to heat a gaseous hydrocarbon in the presence of oxygen and at very high pressures.
Generally, where an electric arc is used as a heat source, the electric arc passes through the hydrogen gas causing the gas to increase in temperature to extremely high temperatures in a very short time. Arc column temperatures commonly reach 8,000 K to 20,000 K.The gas, on leaving the arc and entering the reaction zone, is commonly within the neighborhood of 2,000-5,000 K. Under these conditions, the hydrogen molecules may dissociate partially into hydrogen atoms.
Once the hydrogen leaves the arc, there is an extremely rapid tendency for the hydrogen atoms to recombine into molecules, and in doing so, they give off tremendous amounts of heat. A portion of this heat, in addition to the sensible heat of the gas, is absorbed by the coal particle, mostly via conduction, convection and radiation, thereby causing the coal particle to decompose and more specifically to give off its volatile content, i.e., to devolatize.
It is also well-known and established that process steps and conditions will vary greatly with the type of carbonaceous matter fed to the arc. Heretofore, gaseous and liquid carbonaceous matter were the favored feestocks, as there was no known way of producing a high yield of acetylene at reasonable costs from solid carbonaceous matter. Also gaseous and liquid feedstocks were easier to handle and produced less wear and tear on the arc apparatus.
Thus in summary though the basic process steps are known, it is hypothesized that the mechanics and the kinetics of the process, for example, were not understood well enough, heretofore, to teach one how to maximize the yield of acetylene from solid carbonaceous matter in an energy efficient manner.
The following description represents an understanding of the process directed specifically to solids having volatile content. The necessary process parameters are provided for heating the solid particles as fast as possible to decompose the particle forming volatiles as fast as possible so as to avoid the char forming secondary reactions of these volatiles in the solid particles.
With due recognition of the prior art:
It is an object of the invention to provide a process for converting solid carbonaceous matter into acetylene by decomposing the carbonaceous matter under specific process conditions.
It is yet another object of the invention to describe a process wherein the enthalpies of the source of gaseous heat and heat enthalpies of the carbonaceous matter are adjusted within a specified range in order to increase the yield of acetylene.
It is another object of the invention to perform the process of decomposing solid carbonaceous matter within an electric arc apparatus.
It is yet another object of the invention to provide operating conditions in an electric arc reactor for decomposing solid carbonaceous matter for the production of acetylene.
It is still another object of the invention to provide a process which removes a least 25 percent of the volatiles from solid carbonaceous matter before the carbonaceous matter leaves the reaction zone.
In accordance with the invention, a process is described whereby acetylene is produced from solid carbonaceous matter by decomposing the carbonaceous matter in hydrogen in a reaction where the specific gas enthalpy and the specific carbonaceous matter enthalpy are tightly controlled. In addition, the size of the particles of carbonaceous matter is maintained below a specific minimum in order to cause the removal of more than 25 percent of the volatiles present in the carbonaceous matter within the time it takes the coal and gas to pass through the reaction zone.
The novel features that are considered characterisitc of the invention are set forth in the appended claims; the invention itself, however, both as to its organization and method of operation, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment, when read in conjunction with the accompanying drawings, in which: